In the Syria crisis, Ankara has hinted it might act to head off any vast influx of refugees, but has not spelled out what it would do, beyond seeking U.N. Security Council approval or at least support from its NATO allies for any such intervention.

Turkey toughened its military rules of engagement on the frontier after Syria shot down a Turkish jet in disputed circumstances last month, but has not retaliated directly.

“A buffer zone, humanitarian corridors, a safe haven are all vague concepts which will require international resolutions,” said one Turkish official, who asked not to be named.

“Definitely an aggression from Syria might be a turning point, or a massive influx of refugees,” he said. “The other scenario is the total collapse of the regime in Syria. We will reconsider our measures along the borders and protect them.”

For the moment, Turkish leaders seem wary, but more focused on coping better with the refugees they already host.